Question

我有用户表有 id 字段友情表 frienduser 有 friend1id 或 friend2id 根据谁先向谁发送请求并喜欢表| thread_id - 用户ID 我希望从用户那里选择我的朋友，并喜欢这个话题的人

Answer 1

丑陋的部分是 frienduser 表可以在任一ID上链接。我认为解决这个问题的最简单方法是使用工会。

/* Case 1: My ID is friend1id, my friend is friend2id */
select u2.*
    from users u1
        inner join frienduser f
            on u1.id = f.friend1id
        inner join users u2
            on f.friend2id = u2.id
        inner join likes l
            on u2.id = l.userid
    where u1.id = @MyUserId
        and l.threadid = @MyThreadId
union
/* Case 2: My ID is friend2id, my friend is friend1id */
select u2.*
    from users u1
        inner join frienduser f
            on u1.id = f.friend2id
        inner join users u2
            on f.friend1id = u2.id
        inner join likes l
            on u2.id = l.userid
    where u1.id = @MyUserId
        and l.threadid = @MyThreadId

Answer 2

There you go.

如何结识喜欢我主题的朋友

2 个答案: